Don't assume. Let the dealer know in advance what you expect to see when you go pick up the trailer.
You won't get a manual, there is none. Re the battery, this is a dealer installed item. Typically you get one 12V battery. If you are going to camp without hookups you should request dual batteries. 2 6V golf cart (GC2) batts are the largest that will fit. The dealer will expect to be compensated for the difference in price of course. Note that this will increase your tongue weight by about 70-80 lbs.
You don't mention your tow vehicle or previous towing experience but you will need a brake controller and probably a weight distribution hitch.
You should do a prepurchase inspection, there are usually workmanship issues on these trailers as they come from the factory. someone here will provide you a link to a checklist, I don't have one handy.
Have fun!